libc/AOR_v20.02/math/math_err.c

   1 /*
   2  * Double-precision math error handling.
   3  *
   4  * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5  * See https://llvm.org/LICENSE.txt for license information.
   6  * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7  */
   8
   9 #include "math_config.h"
  10
  11 #if WANT_ERRNO
  12 #include <errno.h>
  13 /* NOINLINE reduces code size and avoids making math functions non-leaf
  14    when the error handling is inlined.  */
  15 NOINLINE static double
  16 with_errno (double y, int e)
  17 {
  18   errno = e;
  19   return y;
  20 }
  21 #else
  22 #define with_errno(x, e) (x)
  23 #endif
  24
  25 /* NOINLINE reduces code size.  */
  26 NOINLINE static double
  27 xflow (uint32_t sign, double y)
  28 {
  29   y = eval_as_double (opt_barrier_double (sign ? -y : y) * y);
  30   return with_errno (y, ERANGE);
  31 }
  32
  33 HIDDEN double
  34 __math_uflow (uint32_t sign)
  35 {
  36   return xflow (sign, 0x1p-767);
  37 }
  38
  39 #if WANT_ERRNO_UFLOW
  40 /* Underflows to zero in some non-nearest rounding mode, setting errno
  41    is valid even if the result is non-zero, but in the subnormal range.  */
  42 HIDDEN double
  43 __math_may_uflow (uint32_t sign)
  44 {
  45   return xflow (sign, 0x1.8p-538);
  46 }
  47 #endif
  48
  49 HIDDEN double
  50 __math_oflow (uint32_t sign)
  51 {
  52   return xflow (sign, 0x1p769);
  53 }
  54
  55 HIDDEN double
  56 __math_divzero (uint32_t sign)
  57 {
  58   double y = opt_barrier_double (sign ? -1.0 : 1.0) / 0.0;
  59   return with_errno (y, ERANGE);
  60 }
  61
  62 HIDDEN double
  63 __math_invalid (double x)
  64 {
  65   double y = (x - x) / (x - x);
  66   return isnan (x) ? y : with_errno (y, EDOM);
  67 }
  68
  69 /* Check result and set errno if necessary.  */
  70
  71 HIDDEN double
  72 __math_check_uflow (double y)
  73 {
  74   return y == 0.0 ? with_errno (y, ERANGE) : y;
  75 }
  76
  77 HIDDEN double
  78 __math_check_oflow (double y)
  79 {
  80   return isinf (y) ? with_errno (y, ERANGE) : y;
  81 }